Technical Field
The present invention relates to semiconductor processing and integration, and more particularly to methods and structures including vertical transistors and long channel analog transistors integrated together on a same chip.
Description of the Related Art
Vertical field effect transistors (VFETs) provide a viable complementary metal oxide semiconductor (CMOS) architecture for node sizes beyond a 7 nm node. In a VFET, current flows vertically. One benefit of VFETs includes that a gate length (Lgate) is decoupled from a contact pitch so that close packed FETs can be made. In a typical system-on-chip (SoC), multiple gate lengths are needed. For example, Lgate of typical logic FETs is around 20 nm. In contrast, the Lgate of analog FETs is about 100-200 nm. Fabrication of a topography of 20 nm Lgate FETs and 200 nm Lgate FETs creates a tremendous challenge for processing.